Magneto-electric telephone



(No'ModelJ' u 2 Sheets-Sheet 1.

T. D. LOCKWOOD 8; T. W.- LANE.

MAGNET() ELECTRIC TELEPHONE.

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` TLD. 'LooKWooD s; T.'W'. LANE] MAGNBTO ELBCTRIGTE-LBPHONE.; l No.2925335. Patented Jan. 22 1884:.

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UNITED STATES THOMAS D. LocKwooD, 'or

MALDEN, MASSACHUSETTS.

PATENT OFFICE.

AND THOMAS V. LANE, OF BOSTON,

l SPECIFICATION forming part of Letters Patent No. 292,335, datedJanuary 22, 1884. l Application filed July 28, 1883. (No modell i To @ZZwil/omit may concern:

Be itknown that we, THOMAS D. LooKwooD, -of Malden, in the county ofMiddlesex and Stated-Massachusetts, andTHoMAs W. LANE, 5 o f Boston,county of Suffolk, and State of Massachusetts, have invented a new anduseful Improvement in Magneto-Electric Teleph on es,

which improvement is fully set forth in following specication.

This invention has reference to that class of articulating telephonescommonly employed as receivers, but capable of use as transmitters aswell, which .comprise avibratory magn'etic diaphragm, or vibratorydiaphragm and I5 armature, and a permanent magnet, with a spool orbobbin of insulated wire on one or both poles 5 and it consists inthecombination, with the permanent magnet of such an instrument, of anadditional Spool or bobbin,

2o which maybe included in circuit with an'electric battery forintensifying and maintaining the magnetism, said additional spool orbobbin being placed on the same pole with the v usual spool or bobbin ofthe telephone.

25 It also consists in 'the arrangement of said two spools or bobbins onthesame soft-iron pole-piece or polepieces,and in close proximity toveach other, the re-enforcing bobbin or f spoolbeing preferably on theinside between `3o the ordinary spool, (which is included in thetelephone-circuit or line-wire,) the object being to make the instrumentas small and compact as maybe (thepole-pieces being smaller than thebody ofthe weight) and as effective. -It further-comprises thecombination, with the instrument having the two bobbins, spools, orcoils, and the battery-circuit including one of said-bobbins, spools, orcoils, of aswitch for breaking the said circuit when the -instru- A 4, asimilar diagram, showing an instrument witha bar-magnet; Fig. 5, a sideview, partly in section, of a hand-telephone constructed in accordancewith the invention; Fig. 6, a dia- 55 gram showing a switch for breakingthe battery-circuit when the instrument is not in use; Fig. 7, a diagramillustrating a portion of a switch-board, with a connector and circuitsadopted for use with the improvedinstru- 6o ment; and Fig. 8, a diagramof the connections when the transmitting-battery is utilize'd.

A is the mouth or ear piece; B, the inclosing-case; C, Figs. 1 and 2, abracket; D, the 65 vibratory diaphragm of magnetic materialsuch as softiron; and M, thepermanent magnet, preferably of steel. Referring to Fig.l, the magnet M is bent so that there are at theV ends projections d d.'In theseV projections 7o the inner ends of the soft-iron pole-pieces c care Xed. The re-enforcing bobbins, spools, or coils b bV are placed onthe pole-pieces at the inner end thereof. The other or ordinary bobbins,a a', are placedon the same pole- 75 pieces at the outer end. Thepole-pieces or cores of the bobbins are bent so that the ends of thebobbins a c face the diaphragm D, while the bobbins b b present theirsides to it.

The'bracket C on the back of the instru- 8o ment is for fastening it toan arm or rod, which passes through the core @,the set-screw f retainingthe instrument in place and permitting it to be adjusted when desired.

The bobbins or re-enforcing coil-sb b are in- 8 5 eluded in the vcircuitof an electric generator or galvanic battery, 7c, and the connectionsare so vmade that the electro-magnetism created by the galvanic currentincreases and maintainsthe magnetism of the magnet. The bob- 9o bins a aare connected to line in any ordinary way. The binding-posts formingconnections with the exterior conductors are lettered g h fijinFigz2.,ffy

Although the circuit of battery 7c may be 95 constantly closed,practically this wouldv in- 'volve a Waste of electric energy,and-therefore switches for breaking the battery-cir'cu it wouldbe'employed. The arrangement of these'is described below. f

In Figs. 4, 5, 6, the bar-magnet Mhas only one pole-piece, c, whichforms a core to both -Ioo bobbins, spools, or coils a and b. As before,the re-enforcing bobbin b is nearest the magnet; the bobbin a nearestthe diaphragm D.

1, 2, 3, and 4, Figs. 4 and 5, are the binding-posts. The battery k isin eluded in a loop between the posts 2 and 3. In Fig. G there are onlythree binding-posts, 1, 2, and 3, the post 3 being connected by the wirem. with the bobbin or coil b, and by the wire Z with the bobbin c. Thepost 2 is connected by wire m with the other terminal of the coil orbobbin I); the post 1 by the wire Z with the like terminal ofthe bobbina. In this gure the circuit of the battery l; is broken, and the twoterminals are connected with the contact-plates 5 and 6, respectively,which are insulated from each other. The switch-leverp ofthe ordinarygravity-switch connects together the two plates when relieved of theweight of the telephone, so that the circuit of the battery l: throughthe bobbin or coil b is complete only when the telephone is in use.\\`hen the transmitterbattery is used to increase and maintain themagnetism of the receiver, the connections are as shown in Fig. S. Thecircuit of the battery k includes the contact-plates 5 6, bindingpost 3,re-eni'oreing bobbin or coil b, bindingpost 2, primary ot'induction-coil 9, and transmitter 10. rlhc telephone-circuit or mainline is divided, one branch passing from the contact-plate 6,binding-post 3, principal bobbin or coil of the telephone-receiver a,bindingpost 1, and secondary of induction-coil to line or ground; theother from the contact 7, through signal-bell 8, to line out or ground.

Vhen the telephone is suspended from the switch-lever p, as shown, thecircuit of battery It is broken, andthe signal-bell 8 only is incircuit. Then the telephone is removed, the battery-circuit is closed bythe switch p between the contact-plates 5 and 6, and the main line iscompleted through the telephone-rcceiver and the secondary of theinduction-coil. For use at the central oiice or at other points a plug,P, is provided. This plug is divided into four parts, which, as they areconnected, respectively, with the binding-posts 1, 2, 3, and 4, arecorrespondingly marked 1', 2', 3', 4. For convenience ot' illustrationthe plug is shown partly in cross-section. The plug is inserted in theopening between the plates 12 and 13, 14 and 15, so that the posts l and4 are connected with the plates 12 and 13, respectively, and the bobbinc (of Figs. 4, 5, and 6) or bobbins c a (of Figs. 1 and 3) are includedin the line-circuit, while the posts 2 and 3 are connected with theplates 14 and 15, respectively, and are thus included in the localcircuit or battery k. It is obvious that a number of lines may center ina switch -board provided with a set of'plates-sueh as 12, 13, 14, and15-for each line-circuit; also, that a single battery may be connectedwith several pairs of plates, 14 and 15.

The details of construction may be greatly modified without departingfrom the spirit of the invention, and portions ofthe invention may beused separately. For example, the particular switches shown need not beemployed; but other known and suitable systems 7o may be adopted to usewith the improved instrument.

Although it is preferred to have the two bobbins or two sets ot' bobbinson the same end or ends of the magnets and on pole-pieces smaller thanthe body of said magnets, and although this construetionisspeciallyclaimed, yet it is obvious that one or more bobbins placed atother parts of the magnet could be used to intensiyand maintain themagnetism 8o thereof.

\Ve claim- 1. The combination, with a telephone comprising a permanentmagnet and two coils or bobbins placed on the same pole of the magnet,of a lbattery included in circuit with one of said coils or bobbins, soas to increase the magnetism of said magnet, the other coil or bobbinbeing included in the telephone circuit or line, substantially asdescribed. 9o

2. The telephone having the two coils or bobbins, or two sets of coilsor bobbins, placed on the same pole-piece or pole-pieces of thepermanent magnet, in combination with an exciting-circuit including. abattery and one coil or bobbin, or one set of coils or bobbins, so thatthe current intensifies and maintains the magnetism of the magnet, andthe telephone circuit or line including the other coil or set of coils,substantially as described. ioo

3. Atelephonc comprising, in combination with the diaphragm, permanentmagnet with one or more pole-pieces, and a bobbin at the end of eachpole-piece, a second bobbin placed on each pole-piece insidethefirst-named bobbin, between it and the end of the body of the magnet,substantially as described.

4. The combination, with a telephone having a magnet and two bobbins orcoils, 011e included in circuit with a battery, so as to in- 11o tensifyand maintain the magnetism, and the other in the telephone-circuit, of akey for opening said battery-circuit when the telephone is not in use,and closing it when the instrumentis to be used, substantially asdescribed.

5. The combination, with a transmitter and its battery, of a telephonecomprising a magnet with two coils or sets of coils, one included in thecircuit of said battery, and the otherin 12o the telephonefcireuit, anda switch for opening the battery-circuit when the instruments are not inuse, substantially as described.

In testimony whereof we have signedv this speciiication in the presenceof two subscribing witnesses.

THOS. D. LOCKVOOD. THOMAS \V. LANE.

XVitnesses:

GEO. XVILLIs Pinnen, D. E. Rica-inns.

